When will your case be reviewed to determine if you are still disabled?
That depends on a number of facts. The intervals between reviews will vary depending on the impairment, severity, and if improvement is expected. Generally every:

• 6 to 18 months after you became disabled if your condition was expected to improve.
• Once every three years if there is a possibility of improvement but improvement cannot be predicted.
• Once every 7 years if the disability is not expected to improve.

Your doctor will determine the severity of your condition. For more information see this government publication:
http://www.ssa.gov/pubs/10068.html

You have been denied Social Security benefits - what can you do?
There are a number of processes available including: reconsideration (you will have someone decide your case which had no part in the first decision), a hearing (the hearing process begins after an applicant for benefits has been denied at the initial and reconsideration levels), an appeal (the Appeals Council review process generally begins after an application for benefits has been denied at the initial, reconsideration, and hearing levels). A brief explanation of the processes and links to the government sites for each:

• Appeal In order to file an appeal, it is important to understand the time frame during which you can ask for one. You have 60 days from the date you receive the letter telling you about our decision to request an appeal. We assume you will get our letter within five days after the date on the letter, unless you can show us you got it later. If you do not appeal within the 60-day time limit, you may lose your right to appeal and the last decision we made becomes final. For example, if you do not ask for a reconsideration within 60 days, you may lose your right to have your case reconsidered.
  The following is the appeal process.
  http://www.ssa.gov/pubs/10058.html#when

• Reconsideration A reconsideration is a complete review of your claim by someone at Social Security (or at the state disability determination services if you are appealing a disability decision) who had no part in the first decision. That person will look at all the evidence used to make the original decision, plus any new evidence. When we make a decision on your reconsideration, we will send you a letter explaining the decision.
  http://www.socialsecurity.gov/OP_Home/reconsideration.html

• Hearing If you disagree with the reconsideration decision, you may ask for a hearing. The hearing will be conducted by an administrative law judge who had no part in the original decision or the reconsideration of your case. The hearing is usually held within 75 miles of your home. The administrative law judge will notify you of the time and place of the hearing.
  http://www.ssa.gov/appeals/hearing_process.html

• Appeals Council review If you disagree with the hearing decision made by the administrative law judge, you may ask for a review by Social Security Appeals Council. The Appeals Council looks at all requests for review, but it may deny a request if it believes the hearing decision was correct. If the Appeals Council decides to review your case, the Council will either decide your case itself or issue an order returning your case to an administrative law judge for further action.
  http://www.ssa.gov/appeals/appeals_process.html#process1

• Federal Court Review Process If you disagree with the Appeals Council's decision, or if the Appeals Council decides not to review your case, you can file a civil suit in a federal district court. This is the last level of the appeals process.
  
  The civil action is filed in the district court of the United States for the judicial district in which you reside or where you have your principal place of business. If you do not reside within any such judicial district or if you do not have your principal place of business within any such judicial district, the civil action must be filed in the United States District Court for the District of Columbia. There is a charge for filing a civil action in Federal court.
  http://www.ssa.gov/appeals/court_process.html

• Your right to representation You may choose to have someone help you with your appeal or to represent you. Your representative may be a lawyer or other qualified person familiar with you and the Social Security program. We will work with your representative just as we would work with you. He or she can act for you in most Social Security matters and will receive a copy of any decisions we make about your claim.
  http://www.socialsecurity.gov/pubs/10075.html

An excellent resource for individuals seeking disability or those who receive benefits, is the government's "Red Book". Some of the important topics are:

• Ticket to work program - A program to aid in rehabilitation and training with many benefits while you are being trained.
• Trial work Period - Enables you to have employment and receive your SSDI while you are attempting to work again.
• Unsuccessful work attempt - An unsuccessful work attempt is an effort to do substantial work, in employment or self-employment, that you stopped or reduced to below the SGA (Substantial Gainful Activity) level after a short time (6 months or less).
  http://www.socialsecurity.gov/redbook/